Lapping machine



May 26, 1942*.` LH. s. IDG

' LAPPING-MAGHINE Filed July 9, 1940 May ze, 1942, www@ Y? 2,284,056

'LAPPING MACHINE Filed July s, 1940 5 sheets-sheet 2 a0 ao "I9 loo 79 38x f 3Q :B44 4o is u 27 o wb I .2 M) (im I3 New n VH --lz5 1 i 'sa 10o151 'o1 qe 153 0 gmc/w60@ f E o ..9

Q Y Herber 5. Indge May 26, 1942. H. s. INDGE i LAPPING MAGHNE 5Sheets-Sheet 3 Filed July 9, 1940 57 'HHL IlIlA Herber 5. Indge wenn' H.s. INDGE l 2,284,056

L APPING MACHINE Filed July 49, 1940 5 Sheets-SheetA v May 26, -1942.

Herbr I ndge 3^# :Humm L. am

May 26, 1942. H. s. INDGE LAPPING MACHINE Filed July 9, 1940 5Sheets-Sheet 5 -vurlan ,yf/

um 89mg w Herber 5. Indge 32 Muem @1Mo/man Patented May 26, 1942 UNITEDSTATES PATENT orifice LAPPING MACHINEl Herbert S. Inilge,Westbo1-o,Mass., assignor to Norton Company, Worcester, Mass., a corporation ofMassachusetts Application July 9, 194o, s,eria1 No. 344,554

6 Claims.

The invention relates to lapping machines.

, and more particularly to a lapping machine for producing highly renedplane surfaces on a work piece.

One object of the invention vis to provide a simple and thoroughlypractical lapping machine in which a plane surface of a relatively largeworl; piece may be rapidly surfaced to a plane surface of extremely highquality. Another object of the invention is to provide a lapping machinein which the work piece is rotated and gyrated in a rotary' or irregularpath while being lapped or abraded by a plurality of rotary and Workpieces by applying a plurality of lapping elements thereto which arereciprocated with a compound reciprocatory movement and simultaneouslyoscillated in arcuate paths relative to the surface of the work piecebeing lapped. Other objects will be in part obvious and in part pointedout hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, as will beexempliiied in the structure to be hereinafter described, and the scopeof the application of which will be indicated in the .following claims.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of this invention,

Fig. 1 is a right-hand end elevation of the improved lapping machineequipped with rotatable lapping wheels, having parts broken away andshown in section to show the operating mechanism thereof Fig. 2 is afront elevation of the improved lapping machine equipped withreciprocating lapping stick adapters;

Fig. 3 is a fragmentary diagrammatic view, showing the hydraulic pipingdiagram and electrical control circuit of the machine;

Fig 4 is a fragmentary pian view, showing the driving mechanism for thelapping heads and spindles;

Fig, 5 is a fragmentary vertical sectional view, on anenlarged scale,vof the driving and operating mechanism for one of the lapping heads;

Fig. 6 is a fragmentary cross-sectional view,

taken approximately on the line 6-6 of Fig.,5,' showing the drivingmechanism'for producing a slow rotation'of the lapping wheel;`

Fig. V'l isa 'fragmentary bottom view, onV an enlarged scale, havinglparts broken away'and shown in section, lof the reduction gear unitfforcontrolling the simultaneous oscillation ofthe I lapping heads;

` Fig. 8 is a cross-sectional-view, taken approximately on the 4Ifnet-8of Fig. 7;

Fig. 9 is a fragmentary sectional view, onan enlarged scale, of the gearmechanism for simultaneously oscillating, the lapping Aheads;

Fig. 10 is a fragmentary view showing the arrangement of the controllever for actuating' the cycle start switch and the stop switch:

Fig. llis a fragmentary vertical sectional view, on an enlarged scale,through one of the lapping heads equipped .with a reciprocating stickadapter;

Fig. 12 isa fragmentary front elevation, on an enlarged scale, showingthe reciprocating lapping stickadapter;

Fig. 13 is a cross-sectional view, on an enlarged scaleftakenapproximately on the line `I3--I3 of Fig. 11;

Fig. 14 is a fragmentaryv sectional view, on

an enlarged scale,l takenapproximately ony the line I4-I4 of Fig.11;,and y Fig. 15 is a fragmentary front elevation, showing the two.lapping heads vequipped with lapping wheels.

The improved lapping machine illustrated .in

4the drawings comprises av base l0 whlchsupports a rotatable worksupporting platen .II together with a. plurality of work Vdriving pinsor studs I2 (only one of which is `shown in the drawings) which engageapertures in a work piece I3 to beflnished. 'The platen Il is'positivelydriven by means of an electrlcfmotorV Il mounted within the base I0 ofthe machine. The motor I4 is preferably mounted on a pivotally-mountedadjustable motorysupport l5 (Fig. 1) which is supportedon a stud orshaft I6.

VThe motor I4 is providedv with a driving. pulley I9 which inV turnserves to rotate a worm 20 (Fig. 3). The worm 2U meshes withY a` wormgear 2| Vand serves to drive the work'su.pport` ing platen II andrevolve and gyrate the work driving pins I2 by means of a mechanismsubstantially the same as that shown inmy prior U. s. Patent No.1,610,527 datedrnecember 14,4

1926. The details of the mechanism for rotating the work supportingplaten Il, which in my prior patent is a lapping element II, and forrotating and revolving the work driving pins I2, have not beenillustrated in the present case since it is noty considered to be a partof the present invention. For details'of disclosure not4contained'herein, reference may bc'had to my prior patent above referredto. W

Apairwof spacedflapping heads 25 and 21 (Fig. 2) vare provided forsupportingeither a` lapping Wheel or a reciprocating lapping stickyadapter (to be hereinafter described) so as to' present a planeoperative end -faceto'lap orv abrade the Work piece I3. In the preferredconare provided Vincluding in addition-to afhead 25 a port for alapping'wheel 28 -or a reciprocatingl lapping stick `adapter which is4also arranged to present a plane operative face. The lapping wheels 28`(only one of Vwhich hasbeen illus'- trated inFigs. l and`3)jarespacedfrom each piece is rotated yandygyrated. Each Vof the Vheads 25and21 is identical inv construction,

consequently' only one of the ,heals'lhas been illustrated "inf" detail.The lapping `wheel' 28 (Fig. 1) isfsupported at oneend/of aV rotatablespindle 29 which isiournalled in an eccentrically Y 4mounted, bearing3|! withina rotatable'sle'eve 3|.

The sleeve 3| is rotatably supported in bearings 'of the arms 4| and 42are each provided with intermeshing gear segments 43 and" by meansofwhich the arms :s ando together with the heads 25 and 21,respectively, and the lapping wheels 26 and 28 may be simultaneouslyoscillated in opposite directions during the lapping operation to imparta relative oscillating movement to each of the heads 25 and 21 duringthe struction, a pairl of spacedf micro-lapping heads;`

' ,Y micro-lapping head 21 which serves as a sup#- 'rotary and planetarymovement of the lapping' wheels Y supported thereby. l

" The frame 38 has a rearwardly extending portion 48'(Fig. 4) whichserves as a support for which is connected by a V-belt 5|-witl multianVelectric driving motor 49. The motor 49 is provided with a drivingpulley 5,0 which is preferably a` multistepped v-type pulley (Fig. 1)

ple' stepped v-pulleys 52 and 53. respectively. The pulleys 52 and 53are supported by vertically l arrangedshafts or spindles 54 and 55,respectively, which arefzrotatably` journalled in the sleeves-4|. A 1 iy i i The spindle or shaft 55 also 'Supports a single Vgroove pulley 56(Fig.` 4)'which is connected l byaV-belt 51 with a single Vgroove pulley58 32jand 33 Within the frame of the head 21'.` The wheel"26 issimilarly. mounted at the lower end l `of a rotatable( vspiridle whichis similarly -jourin a rotatable sleeve whichis in turn rotatablysupported within .the frame Yof the head 25.

Both ofthe heads V21 and25 are arrangedv so that the rotatable sleeyes3| may be rotated at av relatively fast speed whiletheeccentricallymounted'spindles 29 contained therein are rotated at a relativelyslowvsped so that the individual abrasive grains ofthe lapping wheels 'i26 arid28 will be moved in'irregular paths while `in operative contactduring the rotaryand gy.-

spindle 29. VThis portion 65'serves `as a support `for ananti-frictionbearing 66 Vwhich in turn supports a rotatable sleeve 261.' Vv'Ihesleeve 61 carries a gear 68 which is xedly mounted thereratorymovement'of'the workpiece I3.

i jThe Vlapping heads 25 and 21. are preferably arranged Aso4 that theymaybe moved `in asubstantially verticaljdirection toward andfrom the'work"piecef| 3. vQAhollovv column 36 is rigidly` fixed tothe-upperrsurface lof the base I0. Afvernalledin' eccentrically positionedbearings Withmountedwithinjthe'column 36 and'isarranged Atofsupport `thelapping `heads 25 andj21fadja- 'cent toA its: upper lend. The "sleeve31; supports 'a bracket 38`whichserves as a support not/only 'for thelapping headsg'25 and 21 but also su-p-v ports `thefdivingmechanismtherefor to be here-V "inafte'r, described.` f

4 providing a Vfurther irregularvbreak-up motion of the ,lappingAelements to produce Ya higlr- `ly nished workpiece, KVThe heads 25 and21 are each` provided with rearwardlyextend-v `which isV mounted on andVadjacentto the upper end of the sleeve 3| to rotate thesleeve 3| andthereby,v carry the spindle 29 and the lapping wheel28 supported therebyin a plantary path. Similarly, the spindle or shaft 54 (Eig.` 4) isprovided witha `single V-groove pulley 59 which is'connectedgby means ofa V-belt with a single v-groove: pulley (not shown) which is mounted onthe rotatable sleeve supporting the lapping wheel spindle 35 to rotatethe sleeve and therebymove thespindle 35 and the` lapping wheelsupported`thereby in` a planetary path. This Vplanetary drive-for the head 25 hasnot been illustratedin detail, since it is identical to that shown inFig. 1 for the head 21. v

To facilitate a yrelatively 'slow rotary movement 'ofL the lappingwheels 26 and 28 during .their planetary movement, the sleeve 3| isprovided with a reduced cylindrical portion which is concentric with theaxisof the wheel toyand which mesheswith a'stationary internal ringgear69 carriedrby the frame ofthe head 21.r The size of the gear 68 is suchthat it continuously meshes with the-gear 69Qdurin`g the planetarymovement of the spindle 29 as produced by-rotation of its supportingsleeve 3|. flhegear-68 has afsmallernumber of teeththan the fixedgear69, so that asthe gear 68 revolves within) the :stationary gear 69, thevery slow rotarymovement is imparted to the lapping wheel spindle 29toproduce a lrelatively slowrotary movement ofthe Wheel 28 while it isbeing moved planetarily at a comparatively'rapid rate.

The s1eeve61is-s1idab1y keyed to the spindle 29 by means of la key 10 sothat the'spindlemay be moved in a vertical directionrto applythe desiredpressure-'to the' lapping wh'eel 28 while in operative engagementwith'the workpiece I3.

The upper endof ther'wheel spindle supports an ing arms 39 and;40,respectively, whichrfare pivotallysupportedgon a sleeve.,A ,4|a (onlyone `of.which is shownpin detail in. Fig-11)'. The bushing. or's1eeye 4|Vis vertically .arranged and is rotatably supported, vloyf ithebracket., 38.r The arms 39 and 40"`are preferablyarranged as bellcranklevershaving inwardly projecting; arms 4I anclllZ;` respectively(Fig. 4). The inner ends anti-frictiombearing 312.1.-whiclf1in` turnrotatahlyhsupports the casing 13 havinga 'cover plate 14 xedly mountedthereon. Aco'mpression spring,V 15 fissupported at itslower end by'meansof a.,stud;16,'xedly mounted on or integrally formed with thecapor cover 14. f The'upper endo f` Vthe spring15 is supported by a reducedcylindrical portion or stud 11 formed at the lower end of the sleeve 18.'I'he sleeve 1 8 is screw threaded within the upwardly extending housing19. A nut 80 threaded onto the sleeve 18 serves to lock the sleeve 18 inadjusted position relative to the housing 19, so that after the spring15 has been compressed as desired it may be locked in adjusted position.

It is desirable to provide a suitable mechanism for raising the wheelspindle 29 vertically to compress the spring 15 and withdraw the wheel28 from operative contact with the work when desired. As illustrated inFig. *5, a link chain 82 is fastened at its lower end to the stud 16.The u-pper end of the chain 82 is connected to a` pivotally mountedblock 83 which is pivotally supported by means of a stud 84. The

stud 84 is supported on an upwardly extending boss 85 formed integralwith the sleeve 18. The bracket 83 is providedwith an actuating handle86 whereby'when moved in a clockwise direction (Fig. 5), the chain 82may be pulled upwardly in a vertical direction to compress the spring 15and thereby raise the spindle 29 and the lapping wheel 28 from operativeengagement with the work piece. An identical construction is providedfor rotating the wheel spindle 35 and also for raising it in a verticaldirection. It is, therefore, deemed unnecessary to duplicateillustration of the constructional details of this head which areclearly shown in Fig. 5.

A driving mechanism is provided 'for oscillating the gear segments 43and 44 to produce an oscillatory movement of each of the lapping wheels26 and 26 at a comparatively low rate of speed during their combinedrapid planetary and slow rotary movements. A speed reduction unit 90 isdriven by meansv of a multi-stepped V- groove pulley 9| (Fig. l) mountedon the lower end of the shaft of the motor 49. A V-.belt 92 drivinglyconnects the pulley 9| with a multistepped V-groove pulley 93 which ismounted on the lower end of the rotatable driving or input shaft 94 ofthe speed reduction unit 90. A driven or output shaft 95 of the speedreduction unit 90 is provided with a rotatable plate 96 which is in turnprovided with a T-slot 91 (Figs. 1 and 4) which serves as an adjustablecrank plate. A connecting rod 98 is connected at one end by anadjustably positioned stud 99 which is adlustably supported within theT-slot 91 by means of which the crank motion imparted to the end of theconnecting rod 98 may be varied as desired. The forward end of theconnecting rod 98 is connected to a stud |00 which is carried by abracket |0|. The bracket |0| is xedly mounted on the arm 4| adjacent togear segments 43 and 44. As the rod 98 is moved endwise, due torevolution of the adjustable crankpin 99, an oscillating movement istransmitted through the pin |00, to the bracket |0|, to oscillate thearm 4| which in turn oscillates the head 25 and the lapping wheel 28. Atthe same time, through the intermeshing gear segments 43 and 44, the arm42 is oscillated which transmits a corresponding oscillatory vmovementto the lapping head 21 and the lapping wheel 28. By adjusting thecrankpin 99 relative to the plate 96, the length lof the oscillatorystroke of the heads 25 and 21 together with the lapping wheels 26 and28, respectively, may be varied as desired. It will thus be seen thatthe heads 25 and 21 together with their respective lapping wheels 26 and28 are oscillated simultaneously and in opposite directions during l thesimultaneous rotary and planetary movement of the lapping wheels 26 and28.

Any standard speed reduction unit may be employed for reducing the speed`of the motor pulley 9| to a suitable speed for oscillating the lappingheads 25 and 21. As illustrated in the drawings, the speed reducing unitwhich is employed is of thevtype known as the Heliocentric manufacturedby the Universal Gear Corporation of Indianapolis, Indiana. The drivenor input shaft 94 carries a pair of eccentrics |05 and |06 (Fig. 8). Theoutput or driven shaft 85 is fixedly mounted to a, rotatable plungerholder |01 which travels within a stationary internal rack or gearmember which is preferably divided into two parts, namely, the internalracks 08 and |09. The plunger holder |01 rotates within the stationaryracks |08 and |09 at the rate of one tooth for each rotation of theinput shaft 94.

The plunger holder |01 is slotted radially and carries a plurality ofreciprocable plungers ||0 and which are arranged to work into and out ofthe teeth of the stationary racks |08 and ring gear but with definitelydiffering toothv shapes, the teeth of the racks |08 and |09 beingsubstantially wedge-shaped. Due'to the wedging contact between thearrow-pointed plungers ||0 and and the teethof the racks 08 and |09,respectively, a combination of Vsliding and rolling Wedge action isobtained, forcing rotation with a minimum friction to the plunger holder|01 and the output o r driven shaft 95. The input eccentrics |05 and |06force plungers out under load. A pair of retractingrings I|2 and ||3ride in notches formed within the plungers ||0 and respectively, to holdthem back on the no load part of their cycle of operation.

A single eccentric and set of plungers and stationary racks may beemployed but for a maximum smoothness of operation and balance of theworking parts, a universal Heliocentricspeed reduction unit is employed,having two eccentrics as illustrated, each of which actuates a set ot'4plunge'rs and in operative engagement with a pair of stationary racks.Each set of plungers is timed directly opposite or 180 degrees apart andhas a carrying arc of approximately 120 degrecs. The total effect is abalanced distribution of driving power over two-thirds of the completecycle so that a balanced and uniform slow rotation of the loutput ordriven shaft serves to rotate the eccentric or crankpin 98 to oscillatethe heads 25 and 21 simultaneously in opposite directions to cooperatewith the combined rotary and planetary movementsl of the lapping wheels26 and 28 (Fig. 15) to produce the desired breakup movement of thelapping elements, thus producing a highly refined surface on a workpiece.

To facilitate removal of nished work pieces and the insertion of workpieces to be lapped into the machine, a power operated lift mechanism isprovided whereby the lapping heads 25 and 21 may be simultaneously movedto and from an operative position. In the preferred form, a fluidpressure operated mechanism isemployed, cornl 31 ismoved vertically inan -upward direction to raise the head 38 which in turn raises the lapyazsgote ping heads 25 and 21 and also theI lapping wheels 26 and 28,respectively, to an inoperative position.` Similarly, when uid under`pressure is ad-` mitted to a cylinder chamberV above the pisten IIB, adownward movement ofthe sleeve 31,

Withinthe column 35 is obtained, -thusnioving the lapping heads and21ftos'l'iift the lapping wheels26 and 28 into operative engagement withthe work piece I3. I l

In order to counterbalance the weight ofV the y head 38 andthe-partssupported thereon, a'counrelative to the column 31, thecompression of the spring |2I may be adjusted as desired. The com,-pression spring |2I is preferably designed and adjusted so that itscompression is sufficient subvalve |40 is provided in the pipe line |28whereby excess uid under pressure within the iluid system may beexhausted through a pipe |4 into the reservoir |25. g i' "Io facilitatecontrol ofthe lapping operation, anelectrical control `apparatusisprovided 'for controllingnotoly the rotation andl gyration of the workpiece |3 but'also the rotary, `plane tary; and i oscillatory 'movementsof vthe lapping wheel 2E. The valve |30 is preferably`electricallyactuated by means of a solenoid ,|42 which is operativelyconnected to the left-hand end of the valve stem |3|' and a solenoidv|43 which is operatively connected .to the right-hand end `of the valvestem |3l. j Y

Electric` power pis supplied from a suitableV source of power,indicated'by the power lines |50r (Fig. 3),. An electrlcstarter button|5| is provided to ystart the lapping cycle and a stop button|524 isprovided whereby the cycle may be stopped and the laps returnedto aninoperstantially to counterbalance the weight of the head 38 and themechanisms supported thereby.

' `Whenthe head 38 ismoved downwardlyunder the influence of fluid underpressurethe spring |2| is,compressedand'serves as a cushion to reduceor'cushionthe approaching movement of the lappingv wheels 26 and 28 asthey move into operative' contact with the work piece |3.

A fluidjpressure system` is provided for controlling the admission ofuid under pressure tothe ncylinder, `||,5. `A reservoir |25 is formed asa separate unit `at therearof the base I0 of the machine and isconnected to the base by a large tubular member |26 (Fig. 1).. Fluid ispumped from the'reservoirv |25 by a fluid pump |21 which is driven by anelectric motor |28.The pump |21 forcesy fluid under pressure through apipe |29 to a controlvalve |30. The control valve is a piston typevvalvecomprising av valvestem |3| having formed integrally therewith valvepistons |32 and |33-' In the-position of the p arts (Fig. 3), uid underpressure passing throughY the pipe |29 enters a valve chamber locatedbetween the valve pistons |32 and |33 and passes outwardly throughV apipe |34 into the cylinder chamber IIS to move the piston ||6 up-V ativeposition Vat any time during the cycle, if desiredt.V The push buttons,5| and |52 are preferablyoperated by means of a manually operable lever|53 (Figs. 1, 2 and 10) which pro-` jects from the front of the machinebase I0. The lever |53 is pivotally mounted on a stud |54 which islixedlymounted within the` baseY l0 and the push buttons*I |5I` and |521are located within` therbase |0 of the machine. When the leverV |53 ismoved in a counterclockwise direction (Fig. 10), the push button switchI 5I is closedwhich serves to energize the solenoid |42 to shift thecontrol valve |30 vtoward the left (Fig. 3) to cause a downward movementofthe piston` I 8 and the lapping heads 25 and 21 together with theirrespective lapping wheels 28 and 28, and at the same timeto set anelectric time delay relay |55 in motion. i

The downward movement of the head 38 shifts an adjustable stop or dog|56 (Fig. 3) into engagement withV the actuating roller of the normallyopen limit switch |51 to close the switch which inturn closes a circuitthrough a magnetic switch |58 to start the motor I4 and therebyrotatevand/or gyrate the work piece I3 and at the same time startthemotor 49 so as to rotate,

revolve and oscillate the lapping wheels 281:0` produce the desired andpredetermined lapping operation on the work piece |3. Thelappingoperation continuesl forl a predetermined time interval accordingto `the setting of the adjustable electric `time delay relay |55. Aftera predenerminedftime interval has lapsed, the time delay relayv |55serves tov energize the solenoid thus moving the lapping heads 25 and`21 together with their'respective lapping wheels 28 valve chamberbetween the valve pistons |32 and y |33 passes. outwardly through thepipe Y|35 into the cylinder chamberi|20 to produce .a downward movementof the piston .||6 against the,4

compression `ofthe spring` |2Ito move the bracket 38, lapping heads 25and 21, and lapping wheels 26 and 28 into operative lapping engage- |38at the right-handend of the valve |30 (Fig.

3), and out through a pipe |39 which exhausts into the reservoir |25. Anadjustable relief and 28 to I an upward or inoperative position. Duringthis upward movement of the head 38, the adjustable stop ordog |56recedes fr om engagement with' the limit switch |51 and .the switch |51opens the circuit to operate the contact |58 which in turn stops themotors 4 and 49 to stop the movement of the work piece AI3 gaseoso able.in order to attain` one object of this 111;

vention, it iisfdesirable to provide alapping maichine i11j1`-whicheither a rotaryplanetarily moved lappingfwheel or a reciprocatorylapping stick rliayabav employed; depending upon the nature of thework--pieces`to be lapped: The lapping wheels226'; and 28 are preferablysupported by a tapered shank |60 which mates with or nts a taperedVaperture .|6|, formed within-.the lower end of the spindles 2 9 and35,.` respectively, so that the rotatable planetarly lmovable rlappingwheels 28 and26 maybe readily removed from the` machine when desired;

A reciprocatory lapping stick adapter |62 is provided having a hollowtubular shapedjmember provided with an aperture |63'whieh ts anouterperipheral cylndricalcsurface onA the housing 21".V The adapter |62-isprovided with elongated slots |64 andv |65 which are arranged on`diametricallyopposite sides thereof. A pair of studs |66 and v|61 passthrough the elongated I slots` '|64 and' |65, respectively, and arescrew threaded into' vthe housing 21. A'thrust collar |68vis .providedadjacent to the lower end of the housing 21 rand a plurality of studs`|69 r(Figs.-

11 and 13) project downwardly 'fromthe thrust collar-|68; The vstudsy|69are surrounded by compression springs |10,- the lower ends of whicharelocated within apertures.'` or holes |1| formed in theadapter |62. Inthe preferred form'a pluralityof-'studs'l69 are provided which are'symmetrically-arranged (Figjl) so as to'form a yielding :device wherebythe' reciprocable lapi-v ping sticks to befhereinafter described may bemaintained inoperative yielding contact `with" the surface ofthe worklpiece I3 to belappe'd.'

The adapter |62 is provided witl'r'a reciprocable lapping stick4 holderif 13 jwhich serves as a support for `a' pair -of spaced' parallellapping sticks |14"v and |15. Eacliof the lapping vsticks is 'refmovably supported;'dii-l` the reciprocable holder 'Y |13 so thattlne'yfrirayvr be readily removed and replaced'whendesired.. The lappingstick |14 is provided with a' holder |16 having "a surface |11 (Fig. 12)whichmates'with a correspondingly shaped surface onthe under sidef ofthe reciprof cable -holderv |132v The .holder k|16 isyieldingly' held'in `position v'on the reciprocable; holder |13 by niearisoffztpairroflsprings |1811. and |18,^re spectively,l by vmeans of which the r lappingstick holderv |16maybereadily detachedwhen it is desired to'replace thevlapping stick with a new stick or'a stick having differentabradingcharacteristics. Y y i ff w Similarly, the 'lapping stick |15 is mountedin a holder vIlm-whichV is similarly yieldably held in f position onvthe reciprocable holder- |13 in the same manner that thelappinglstick|14 and its supporting rholder |16 are mounted. Only one of themountings has-been shown in detail; since they are identical inconstruction andit is not deemed Vnecessary Ito duplicatetheillustration. The reciprocable holder' |13 is arrangedto reciprocatelongitudinally in a guideway A| 8| formed in a lower end plate |82 fixedto thelower surface of the adapter |62. A member |83 is fixed to theupper surface of the lreciprocable holder |13 `and formsa slidev memberwhich mates'w'ith the slide surface |8| and also slides longitudinallyon 'the plate |82, thuscooperating with thereciprocable holder |13 toform slideways for producing-the Vdesired 'reciprocatory movement of thelapping sticks"|14 and |15.

In order to impart a reciprocatory movement to the lapping sticks |14and |15, a suitable connection is provided between the spindle 29 andthe reciprocable lapping stick Vholder |13. kThe Vmember |83 is providedwith a transversely extending cut-out portion, forming two thrustsurfaces |84 and V|85 (Fig. 14) Within which a ring |86 islocated. Thering |86 serves as a support for an anti-friction bearing |81. A taperedshank |88 mates with the tapered aperture |6| in the lower end of thespindle 29. A crankpin `|821 is formed integral with the shank membery|88 and nts within the central aperture inthe anti- 1` friction bearing|81. It will be readilyapparent from the foregoing disclosure thatl whenthe spindle 29 is rotated,l the crankpin |89 will be e revolvedto imparta reciprocatory movement to and the spindle29 at a comparatively slowrate of speed, `a compound reciprocatory movement will beV transmittedto the lapping sticks |14 and 59 ducing a plurality of compound motionswhich v |15. VThe rapid rotation of the sleeve 3| will imparta'comparatively rapid reciprocation of `a relatively long stroke to thelapping sticks |14 and |15 `and simultaneous therewith the slow rotationof the spindle 29 will impart a reciprocatory movement tov the lappingsticks |14 and |15-`Which is of a relatively slow speed through aIcomparatively short stroke. It will be readily apparent from theforegoing disclosure vthat the reciprocatory lapping'sticks |14 and |15will be provided with a compoundreciprocatory stroke which'4 produces abreak-#up'action in abrading or lapping a workpiece. In addition to thecompound reciprocatory strokejof the lapping sticks |14 and |15, the twoheads 25 and 21 are oscillated simultaneously and in the oppositedirection,l thus imparting a third relative motion of theflapping sticks|14 and |15. At the'salme time the compound reciprocatory andoscillating movement is imparted to the lapping sticks |1,4and |15,` thework piece I3 is rotated and gyrated through an irregular path, thusprobreaklup theaction Aol? the individual abrading particles of thelapping sticks so as to produce a highly refined ultra-iinished surfaceon the work piece |3 being lapped.

It will be readily apparent from the foregoing disclosure' that thereciprocable lappingA stick adapter |62 may be readily mountedon theheads 25 and 21 by removing the lapping lwheels 26 and 28 and slidingthe tubular members'of the ref ciprocable lapping stick adapters |62into supporting engagement-.with the housings 25 and 21,* after whichthe studs |66 and |61 are inserted in place, thus holdingthe adapters|62 in position `for aflapping operation.` WhenV the adapters |62 arevremoved intoan operativeposition, the tapered shank |88 is moved intooperative engagement with the tapered aperture |6| so that the combinedrotary motion of the spindle 29 and the planetary motion of the sleeve3| will be imparted to produce a compound reciprocatory movement of thelapping sticks |14 and |15. Similarly, the adapter |62 may be readilyremoved from the machine by removing the studs |66 and |61 andwithdrawing the requiring .correction as follows: In the drewings,insert the figure CERTIFICATE OF CORRECT ION."

Patent No. 2,28u,o56. Mayae, letz.

. HERBERT s. INDGE.

It is hereby certified that error appears in the above numbered patentshown helow as a part of Sheet 2 same Sheet 2, Figure 2, for thereference numeral "160" read l60a-; Sheet 5 of the drawings, Figure l2,for the numeral "177" designating a springread -l78a; and that thesaidLetters Patent should be read with this 'correction therein that thesame may conform to the record of the case in the Patent Office.

Signed and sealed this 11th day of August, A. D. -19LL2.

l Y Henry Van Arsdale',

(Seal) Acting Commissioner of Patents.

